The present invention relates to course-to-steer guiding devices for sailing vessels and the like.
The invention provides a centered on-course indication and steer left or right commands, by responding to which the helmsman may maintain the sailing vessel on a preset angle relative to the apparent wind. The invention also accurately detects and indicates the head to wind condition.
It is a characteristic of sailboats that, for any wind strength and sea state, maximum speed made good to windward is achieved on two courses. These two optimum courses are symmetric with respect to the direction of the wind and occur, on high performance sailing vessels, at approximately 30 degrees relative to the apparent wind. Since sailing at angles other than the optimum courses results in lower speed made good, it is particularly important during racing to be able to very rapidly make heading adjustments in response to wind shifts, in order to hold the optimum course (port or starboard) as consistently as possible and for as large a fraction of race time as possible.
In prior art devices wind vanes coupled to remote reading indicators have been used to display to the helmsman the direction of the apparent wind relative to the center line of the sailing vessel. On seeing a change in time displayed angle, the helmsman must go through the mental process of comparing the indicated angle to the desired course and then resolving whether he ought to bear left or right. This requires concentration and practice. Furthermore, the helmsman's response may be erroneous, because the ever present ambiguity between error and the required correction may cause him to turn the wrong way. What is more, the helmsman's response is not likely to be as spontaneous as when he is reacting by reflex to steering commands.
A further disadvantage of these devices is that the on-course conditions are represented on the indicator by off-center pointer positions, typically at -30.degree. (while on port tack) and 30 (on standard). The centered pointer position, which would be the logical choice for on-course, is associated with the unusable head to wind condition. This latter disadvantage is partially overcome in another prior art device which provides an adjustable control whereby the pointer may be biased to take a centered position while on-course. However, separate adjustments must be made for the port and starboard tacks with the outcome that the helmsman, or his crew, must reset this control each time the sailing vessel changes tacks.